A Red Alga With no U1: A Simpler Model for RNA Splicing
Jan 15, 2014
3:30PM to 4:30PM
Date(s) - 15/01/2014
3:30 pm - 4:30 pm
Title: A Red Alga With no U1: A Simpler Model for RNA Splicing
Speaker: Dr. Stephen Rader
Institute: University of Northern British Columbia
Location: ABB 102
The last 15 years have seen quite literally a revolution in our understanding of how gene expression – the cellular decisions about which proteins to make – is regulated. From the protein primacy paradigm that held sway since the pioneering experiments of Jacob and Monod, we have recently come to realize that the majority of gene expression decisions are actually controlled by RNA.
One of the important steps in eukaryotic gene expression is the removal of non-coding regions from pre-messenger RNA, a process known as pre-mRNA splicing. Interestingly, the machinery that carries out this process is built around five small, nuclear RNAs (snRNAs), raising the possibility that RNA splicing, like protein synthesis, hearkens back to a pre-biotic RNA world in which RNA carried out both the information transmission function of DNA and the catalytic function of proteins.
While the last ten years have seen the completion of the â??parts listâ? for the splicing machinery, we still understand very little about what any of the parts do, largely because of the huge complexity of this machinery (over 200 proteins are involved in humans) as well as its highly dynamic nature (it assembles from its component parts on every substrate molecule). My lab has recently discovered that a little-studied red alga has a dramatically reduced complement of splicing factors, with only ~40 proteins. Strikingly, we have been unable to find one of the snRNAs, known as U1, raising the possibility that this alga either contains a primordial splicing apparatus, or that selective pressure has resulted in its elimination. Either way, we expect this much simpler splicing system to accelerate our understanding of this fascinating process.